Abstract The recent use of electric motors for vehicle propulsion has stimulated the development of numerical methodologies to predict their noise and vibration behavior. These simulations generally use models based on an ideal electric motor. But sometimes acceleration and noise measurements on electric motors show unexpected harmonics that can generate acoustic issues. These harmonics are mainly due to the deviation of the manufactured parts from the nominal dimensions of the ideal machine. The rotor eccentricities are one of these deviations with an impact on acoustics of electric motors. Thus, the measurement of the rotor eccentricity becomes relevant to understand the phenomenon, quantify the deviation and then to use this data as an input in the numerical models. An innovative measurement method of rotor eccentricities using fiber optic displacement sensors is proposed.
Abstract Cycle to cycle variations is always a cause for concern in port injected SI engines. Earlier studies in this field suggest that cycle by cycle variations in the position and growth rate of flame kernel has a significant role in the cycle by cycle variations in the pressure curves. Researchers are always interested in understanding the fluid flow and combustion characteristics in a running engine to study these variations in detail. Due to its simplicity in adaptation, fiber optic spark plug enables the researchers to study the effects of charge motion on the developing flame kernel at relatively less cost and effort. In this paper 8 channel fiber optic spark plug was used to measure and understand the flame kernel development. Flush mounted pressure transducer is also installed to measure in cylinder pressure data.
Abstract Fiber optic physical contact connection technology has been used with multimode fiber in civilian aircraft for over 30 years with very good proven reliable performance. The extensive use of singlemode fiber (SMF) in FTTx Telecom market rollouts speeds up the development of passive optical components which significantly decreases the cost, expands capability and increases the reliability level of singlemode components. SMF transmission seems mandatory for future applications even in mil-aero and other harsh environment applications due to increased data rate requirements and new sensors applications. In harsh environment applications, is it realistic to use SMF with cores that are 30 times smaller in area compared to multimode fiber (MMF) when highly exposed to contamination? The present paper presents a technology of beam expansion interconnection that mixes a physical contact (PC) with an expanded optical surface.
Abstract Recently, there has been an increasing interest in Fiber Optic Sensors (FOS) for aircraft applications. Many of the FOS are based on different transducer mechanisms and hence, employ sensor-specific readout systems. However, for ease of maintenance and cost saving purposes, a ‘universal interrogator’ that can be used with at least a large sub-group of sensors is the preferred option for deployment in aircraft. Oxsensis has been developing sensors for harsh environments with focus on land based gas-turbine monitoring and combustion control and more recently is also looking at applying its technology to other areas such as Aerospace and Oil & Gas. In this paper we report on recent progress on the development of a number of FOS and how these could find application in aircraft with a ‘universal interrogator’ concept in mind.
The tenets of IEC 61300-3-35 have influenced and contributed to numerous standards. These include: a.) the importance of cleaning the fiber optic connection, b.) the concept of diameter of debris or contamination, and, c.) the area of the end face to be cleaned, d.) methods of cleaning. As capacity and bandwidth expand, deployments updated, and new technicians trained, a clear understanding of several other tenets of precision cleaning the connection may also be considered. There are many types of debris and contamination. Some are dry Figure-1 and others are fluidic Figure-2. Debris on an end face may also be present in combination Figure-3. The cleaning procedure should strive to be a first time event. A best practice procedure can be identified that does not require multiple techniques and numerous attempts.
Helicopter rotor systems are increasingly using flexible composite structures to provide the required control movement for the rotor blades. These structures such as rotor head flex beams can experience very high surface strains, which can be in the order of 15,000 με. This makes it difficult for them to be monitored using conventional surface bonded strain sensors. Helicopter rotor hubs incorporating thick composite flexures are subjected to delamination failures with correlate to bending excursions. Measurement of this deflection could be used to predict remaining useful life of the flexure and other hub components. Previous efforts to measure surface strains using fiber optic sensors led to mixed results and prompted an effort to explore embedded sensors. As part of a Vertical Lift Consortium project, the authors tested proof of concept manufacturing specimens to establish the ability of the sensors to survive the cure process in a closed cavity mold tool.
Traditional power train development work is concentrated mainly on test bed and on chassis dyno. Though we can simulate a lot of real world conditions on testbed and chassis dyno today, on road application work willis gaining more attention. This means that strategies and tools for invehicle testing under real world conditions are becoming more important. Emission, performance, fuel economy, combustion noise and driving comfort are linked to combustion quality, i.e. quality of fuel mixture preparation and flame propagation. The known testing and research equipment is only partly or not at all applicable for in-vehicle development work. New tools for on the road testing are required. Following, a general view on in-vehicle power train testing will be given. Additionally, new ways to investigate cylinder and cycle specific soot formation in GDI engines with fiber optic tools will be presented.
Lighting and illumination systems using visible Lasers light sources are being developed under a number of US Navy programs to reduce the ship's costs including acquisition, installation, operation, and maintenance. Recent advances resulting from research initiatives funded thru the Office of Naval Research Mantech program and a Navy SBIR project are making broader applications of this technology feasible, including possible transition into aircrafts for position, landing, anti-collision, cargo loading, wing icing detection, and interior lights. The development of these lasers is being driven by the high definition projection industry, with substantial investments made to bring the technology to broad scale implementation, and with the anticipated increase in product availability and decrease in costs. The laser systems offer significant advantages over fiber optic systems using other light sources including metal halide and LEDs.
For most data and telecom fiber optic applications the physical contact (PC) concept is preferred for all indoor and even some outdoor applications. But when these connectors are subjected to a harsh environment, the performance of standard PC connectors has proven unreliable in many applications due to their sensitivity to contamination. The subject for this paper is the design of a small form factor expanded beam (EB) fiber optic contact pair suited for operation in a challenging environment. The contacts conform to the dimensional envelope of MIL-PRF-29504/4/5D and employ a separable lens unit design which provides the option for field-installable terminations. The EB concept typically exhibits a higher loss than the PC connection, but preliminary results of the new design indicate that the size 16 termini pair using 1.25mm lenses and ferrules yields a very good loss performance.
Fiber optics has been a viable technology for data communication applications in many environments including aircrafts, providing higher bandwidth, longer transmission distances, EMI/RFI immunity, and lower weight than copper cables. Until recently however fiber optics was not a viable transmission medium to efficiently distribute light for illumination on aircrafts. Fiber optic lighting systems, referred to as the Remote Source Lighting technology have been installed on US Navy vessels including the LPD 17 class, the Italian Multi-Mission Frigate FREMM class, and the DDG 1000 class. Optical fibers can offer advantages over conventional lighting systems that use copper cables due to safety, lower maintenance, EMI/RFI immunity, no possibility of short circuits or sparks, lightweight, and low operating costs. Higher procurement costs, primarily driven by the 37 fibers optical cable, have prevented a broader usage on naval vessels and for other applications including aircrafts.
To compliment the development of the single channel small form factor size 16 optical Expanded Beam (EB) pin and socket contacts, we have explored the possibility of designing a multi-fiber high density lensed termini (HDLT). This paper describes the design efforts of an insert containing two ferrules accommodating a total of 24 fibers and mountable into a size 8 Quadrax cavity of a 38999 style connector. To take advantage of the expanded beam concept and to keep the design cost effective, the ferrules are molded with a 12 fiber v-groove array positioned behind integral lenses. Originally, the ferrules were designed for the relative benign environment of datacom applications. Therefore, in order to accommodate the broader operational environment of arospace applications which includes mechanical vibration, thermal cycling and high humidity exposure a suitable epoxy had to be identified. Design details, proposed solution, and initial test results are discussed.
Successful use of fiber optic interconnects in high-performance platforms and applications depends on viable technologies for their repair and installation. Splicing is often desirable, either to repair a damaged interconnect or to install it, particularly where it is difficult or impossible to access all necessary locations for complete removal and replacement. However, reliable aerospace cable splices must endure conditions as adverse as those for which the original cable was specified. In addition, the splicing technology must be usable with a high degree of reliability under difficult aerospace working conditions. Mechanical splices have shown some promise for the repair of multi-mode aerospace fiber cables, but they face daunting difficulties in splicing single mode fiber cables, which are being ever more seriously considered for new and upgraded systems.
This paper presents an investigation into the feasibility of utilizing commercial off the shelf (COTS) components to implement an optically linked embedded electromechanical actuator (EMA) for aircraft flight control. A joint 1990s USAF, USN, NASA Electrically Powered Actuator Design (EPAD) program sought to replace hydraulically powered aircraft actuators with those powered electrically, either Electrohydrostatic (EHA) or Electromechanical (EMA). A follow-on NASA research effort in 1992 sought to then replace the electrical control links associated with the EHA/EMA with fiber-optic technology . Attempts at implementing an optically-linked EMA while successful, experienced technical challenges and exposed fundamental limitations and shortfalls in some of the COTS technologies available at that time.
KALFOS - A Validation Facility for Strain Transfer Characterization of Surface-Applied Strain Sensors
Strain sensors embedded in or attached to structural components have to measure the real deformation of the structure over the whole period of use. The user must know how reliably installed sensors provide strain measurement results. For this purpose, test facilities or coupon tests are used. In order to characterize the strain transfer quality from the host structure into surface-applied strain sensors, a unique testing facility has been developed. This facility can be used both for fiber optic and resistance strain sensors. Originally developed for fiber Bragg grating based sensors, the KALFOS facility (= \bc\ba\blibration of \bfiber \boptic \bsensors) uses Digital Image Correlation (DIC) and Electronic Speckle Pattern Interferometer (ESPI) as unbiased referencing methods. It is possible to determine experimentally the strain transfer mechanism under combined thermal and mechanical loading conditions.
Laser-Induced Phosphorescence Measurements of Combustion Chamber Surface Temperature on a Single-Cylinder Diesel Engine
Non-intrusive, crank-angle resolved measurements of piston temperature have been performed in a single-cylinder direct-injection (DI) Diesel engine operating under highly-dilute low-temperature combustion (LTC) conditions. The laser-induced phosphorescence (LIP) technique exploits the temperature-dependent characteristics of rare-earth or transition metal doped ceramic phosphors. This paper describes the calibration procedure and subsequent application of the technique to measure piston surface temperature in a single-cylinder, optically-accessible Diesel engine for various parametric variations including fueling rate and injector nozzle characteristics. In addition, measurements of the nozzle tip temperature of a Diesel injector are also reported. Furthermore, a fiber-optic solution has been developed which enables piston surface temperature measurements to be performed in standard metal (i.e. non-optical) single-cylinder and multi-cylinder engines.
The cylinder head gasket with integrated combustion pressure sensors (CHGICPS) reported here targets advanced engine controls and in particular those based on the HCCI, PCCI, or LTC combustion principles, for gasoline, diesel, and alternative fuel engines. Due to the fiber optic combustion pressure sensor's (CPS) accuracy at low pressure during compression integrated into the CHGICPS, this device aims at in-cylinder prediction of mass air flow as well as in-cycle closed loop control of pilot fuel injection in a diesel engine. This paper reports on a replaceable CPS which allows installation and removal from the cylinder head gasket (CHG) without the need for removing the engine head. At the same time the distance layer thickness of CHGICPS is minimized to 2.5 mm and 3.4 mm, depending on the access ability and space constraints around coolant and lubrication ports in the engine.
The aerospace industry has an every increasing appetite for bandwidth for on board networking for their aircraft. Future projections suggest that aircraft of the future tied into the information grid will require terahertz of intra aircraft bandwidth connecting to hundreds of nodes. This paper describes some of the lessons learned by observing the commercial industry's thirty to forty year history deploying networks. It concludes by describing the standards development effort by the Society of Automotive Engineers (SAE) to develop a wavelength division multiplexed (WDM) local area network (LAN) standard over standard telecommunications grade optical fiber.
The feasibility of extended human presence on the Moon and Mars depends critically on in-situ resource utilization (ISRU) to mitigate the high interplanetary transportation costs. Key resource requirements include water, oxygen, fuel and a variety of building materials. This paper discusses the robotic instrumentation associated with the LORE (Lunar Origins and Resource Exploration) miniature payload proposed for JAXA's Selene-2, and the potential follow-on CSA INUKSHUK landed-Mars mission. LORE would for the first time systematically explore the lunar surface and subsurface ice distribution, dust, mineralogy and resources using combined UV/VIS/MIR reflectance spectroscopy. The spectral differences between ilmenite and other lunar minerals in the ultraviolet region will be exploited for mapping ilmenite distribution and abundances on the lunar surface and subsurface.
Rapid In Situ Measurement of Fuel Dilution of Oil in a Diesel Engine using Laser-Induced Fluorescence Spectroscopy
A technique for rapid in situ measurement of the fuel dilution of oil in a diesel engine is presented. Fuel dilution can occur when advanced in-cylinder fuel injection techniques are employed for the purpose of producing rich exhaust for lean NOx trap catalyst regeneration. Laser-induced fluorescence (LIF) spectroscopy is used to monitor the oil in a Mercedes 1.7-liter engine operated on a dynamometer platform. A fluorescent dye suitable for use in diesel fuel and oil systems is added to the engine fuel. The LIF spectra are monitored to detect the growth of the dye signal relative to the background oil fluorescence; fuel mass concentration is quantified based on a known sample set. The technique was implemented with fiber optic probes which can be inserted at various points in the engine oil system. A low cost 532-nm laser diode was used for excitation.
Optical Backscatter Reflectometry as a Measurement Tool for Fiber-Optics in Avionics and Aerospace Applications
We present optical backscatter reflectometry, a commercially available method for testing and troubleshooting of short haul fiber optic links. Short-length optical communications networks like those in avionics and aerospace applications require frequent heath assessment. Precise recognition and localization of faults, accurate measurement of loss though the link are critical to maintaining signal integrity. The optical backscatter reflectometry method makes it possible to detect and localize bends, breaks, bad splices, and poor connections with up to 10 micron spatial resolution with no dead zone. Links can be measured with 1 mm resolution over up to 2000 m of fiber length. In addition to fault location and loss measurement, this measurement technique makes possible distributed temperature and strain measurements along standard optical fiber. We will provide measurement examples demonstrating capabilities not currently supported by conventional measurement tools.
Gas Temperature Measurement in a DME-HCCI Engine using Heterodyne Interferometry with Spark-Plug-in Fiber-Optic Sensor
Non-intrusive measurement of transient unburned gas temperatures was developed with a fiber-optic heterodyne interferometry system. Using the value of the Gladstone-Dale constant for DME gas and combustion pressure we can calculate the in-cylinder temperature inside unburned and burned region. In this experimental study, it was performed to set up a fiber-optic heterodyne interferometry technique to measure the temperature before and behind the combustion region in a DME-HCCI engine. At first, measured temperature was almost the same as the temperature history assuming that the process that changes of the unburned and the burned are polytropic. In addition, we measured the temperature after combustion which of condition was burned gas with DME-HCCI combustion. The developed heterodyne interferometry used the spark-plug-in fiber-optic sensor has a good feasibility to measure the unburned and burned temperature history.
Inukshuk Landed Robotic Canadian Mission to Mars using a Miniature Sample Analysis Lab for Planetary Mineralogy and Microbiology
This paper discusses the Inukshuk landed rover mission to Mars that is currently undergoing the Phase 0 mission study for the Canadian Space Agency. The Inukshuk landed rover mission addresses key science themes for planetary exploration; focusing on the search for hydrated mineralogy and subsurface water sites that can provide evidence of past or present life. New exploration and science will be accomplished using an innovative tethered combination of a small rover and a self-elevating sky-cam aerostat. The elevating visible (VIS) imager, at about 10 m altitude, will provide an informative high-resolution 2-D view of the rover below and surrounding terrain to greatly assist the semi-autonomous navigation of the rover around obstacles and selection of sites for detailed subsurface exploration.
19-Color H2O Absorption Spectrometer Applied for Real-Time In-Cylinder Gas Thermometry in an HCCI Engine
1 ABSTRACT An all fiber-optic sensor has been developed to measure H2O mole fraction and gas temperature in an HCCI engine. This absorption-spectroscopy-based sensor utilizes a broad wavelength (1320 to 1380 nm) source (supercontinua generated by a microchip laser) and a series of fiber Bragg gratings (19 gratings centered on unique water absorption peaks) to track the formation and temperature of combustion water vapor. The spectral coverage of the system promises improved measurement accuracy over two-line diode-laser based systems. Meanwhile, the simplicity of the fiber Bragg grating chromatic dispersion approach significantly reduces the data reduction time and cost relative to previous supercontinuum-based sensors. The data provided by the system is expected to enhance studies of the chemical kinetics which govern HCCI ignition as well as HCCI modeling efforts.
The PressureSense Glow Plug combines a miniature cylinder pressure sensor with the automotive glow plug. The 1.7mm diameter fiber optic-based sensor is welded into the glow plug heater and the signal conditioner is encapsulated into a “smart connector” located on the top of the glow plug body. The sensor offers accuracy better than +/-2% of reading between 220 bar and 5 bar and +/-0.2 to +/-0.5 bar error for pressures below 5 bar. The performance of “dummy” as well as glowing and pressure sensing devices was evaluated on various engines and over a wide range of engine operating conditions.
Researchers at Luna Innovations Inc. and the National Aeronautic and Space Administration's Marshall Space Flight Center (NASA MSFC) are developing an integrated fiber-optic sensor system for real-time monitoring of chemical contaminants and whole-cell bacterial pathogens in water. The system integrates interferometric and evanescent-wave optical fiber-based sensing methodologies to provide versatile measurement capability for both micro- and nano-scale analytes. Sensors can be multiplexed in an array format and embedded in a totally self-contained laboratory card for use with an automated microfluidics platform.
Advanced Integrated-Optic and MNT Technologies for the Infrared Spectral Monitoring of Spacecraft Vital Life-Support Systems and Remote Astronaut Health Diagnostics
Manned space systems have many requirements for the monitoring of vital life support systems including quality of cabin air and the recycled water supply, as well as direct monitoring of vital indicators of astronaut health. Infrared (IR) spectroscopy is an attractive monitoring technique because it requires minimal consumables while providing relatively high chemical specificity for the detection of a wide variety of biochemicals using the characteristic vibrational modes of chemical bonds. For space-based systems, the important drivers are reliability, power consumption, mass and simplicity of operation. MPB has advanced its IOSPEC™ technology for miniature integrated IR spectrometers to provide performance comparable to large bench-top IR systems but in a compact and ruggedized footprint weighing under 2.5 kg.
A heterodyne interferometry system with a fiber-optic sensor was developed to measure the temperature history of unburned gas in a spark-ignition engine. A polarization-preserving fiber and metal mirror were used as the fiber-optic sensor to deliver the test beam to and from the measurement region. This fiber-optic sensor can be assembled in an engine cylinder head without a lot of improvements of an actual engine. Adjustment system in the sensor was revised to face the distributed index lens with metal mirror. Before the flame arrived at the developed fiber-optic sensor, measured temperature was almost same with the temperature history after the spark, assuming that the process that changes the unburned gas is adiabatic. In situ unburned gas temperature measurements before knocking in a commercially produced SI engine can be carried out using developed fiber-optic heterodyne interferometry system.
The objective of this study was to investigate the use of a fiber optic based sensor, ShapeTape, as an instrument for measuring abdominal and chest deflection, and to compare it to the current instrument used in impact biomechanics applications, the chestband. Drift, pressure, and temperature tests were conducted for ShapeTape alone, whereas quasi-static and dynamic loading tests were conducted as comparison tests between the chestband and ShapeTape. The effects of drift and temperature on ShapeTape were very small, averaging 0.26% and 1.2% full scale changes respectively. During the pressure test at a load of 1000 N the ShapeTape sensor tested experience a 7.47% full scale voltage change. The average errors in reporting maximum deflection of the chest form during the quasi-static loading tests were 3.35% and 1.64% for ShapeTape and the chestband respectively.